Machine for threshing tobacco leaves and separating the threshed tobacco



United States Patent [1113,548,839

[72] Inventor OIOTKRI'ISSOII 3,386,451 6/1968 Pietruccietal 131/146 FOREIGN PATENTS 25$ 3212 .5 1,502,817 10/1967 France 131/146 45 Patented Dec. 22: 1970 Primary Examiner-Samuel Koren [73] Assignee ArencoAktiebolag Assistant Examiner-James l-l. Czerwonky Stockholm-Vallingby, Sweden Attorney-Sughrue, Rothwell, Mion, Zinn & MacPeak [32] Priority 0ct.31, 1967 2:32: ABSTRACT: A machine for threshing tobacco leaves and [54] MACHINE FOR THRESHING TOBACCO LEAVES AND SEPARATING THE TIIRESHED TOBACCO separating the threshed tobacco, comprising a threshing chamber, a threshing wheel in said threshing chamber, and means to rotate said threshing wheel around a vertical shaft, all mounted within a tubular housing. Means are provided to supply tobacco leaves to said threshing chamber, and a separating chamber surrounds at least the major part of said threshing chamber. The threshing chamber has a substantially cylindrical open-topped wall and is directly connected with said separating chamber partly by a circumferential outlet opening for the threshed tobacco in the lower part of the wall, provided with a grid, and partly by an annular opening between the upper part of the threshing chamber wall and a vertical cap. The cap is tubular in shape and open at both ends and the open, upper end extends centrally in the housing and above the separating chamber. The open, bottom end of the cap extends into the open-topped part of the threshing chamber.

MACHINE FOR THRESHING TOBACCO LEAVES AND SEPARATING THE THRESHED TOBACCO The US. Pat. No. 3,229,698 describes a machine for threshing tobacco leaves and separating the threshed tobacco, comprising a threshing chamber having an opening for the supply of tobacco leaves, in which chamber a rotating threshing wheel is arranged around a vertical shaft. The chamber is connected direct to a surrounding annular separating chamber, partly by an outlet opening provided with a grid for the threshed tobacco and partly by an annular opening between the upper part of the threshing chamber and a cap situated above the threshing chamber coaxially with the same, wherein the diameter of the cap is less, at leastat the lower part thereof, than the diameter of the threshing chamber.

To obtain satisfactory separation of the threshed tobacco it must be possible to adjust the air speed in the upper part of the separation chamber, where the cap is situated, to a magnitude, which, among others, is dependent upon the sort of tobacco to be treated. It has been found difficult, however, especially in treating tobacco for the manufacture of cigarettes, to avoid too high air speeds in the 'upper part of the chamber, if the capacity of the machine is to remain unchanged.

The present invention affords a simple solution to this problem by making the cap tubular in shape and open at both ends. ln this way the separating air will be divided into two generally parallel branches, namely one stream, which passes through the upper part of the chamber in the usual way and one stream, which passes throughthe tubular cap. owing to the flow conditions in the machine the air speed in the cap becomes high when the load on the machine is high, and the desired reduction in the air speed in the upper part of the chamber can be achieve achieved without difficulty.

Because of the abrupt change in direction of the air at the inlet of the cap portions of tobacco leaves with attached stems are prevented from leaving the cap together with the air. if necessary, this effect can be amplified by causing e the lower part of the cap to extend down in the upper part of the threshing chamber, which in such case is provided with a tubular casing. To prevent the area of the cap from becoming too small, it is convenient to provide the machine of the invention with the opening for the supply of the tobacco leaves in the tubular casing.

The invention will now be described in conjunction with the accompanying drawing, which diagrammatically illustrates an embodiment of the invention in section.

The illustrated machine has a tubular, upstanding housing 1, which tapers at the top and the upper, open end of which is sealingly connected to the suction pipe 2 of a fan not shown. In the housing 1 there is a threshing chamber 3, including a threshing drum 5 rotating around a vertical shaft 4 and a tubular casing 6, which is arranged so that a vertical annular separating chamber 7 is obtained between the housing 1 and the threshing chamber 3, which is provided with an outlet opening 8, covered by a grid 8 and extending substantially around the whole periphery of the chamber 3. The separating chamber 7 extends down between a lower casing 9 and the housing 1 and upwards between a tubular cap 10, situated above the chamber 3, and the housing 1. The cap 10, which is open at both ends, is firmly fixed to the housing 1 by a vertical plate 11 situated immediately above a section 12, which is shielded from the separating chamber and in which is arranged an opening to the threshing chamber 3. Deflectors l5 are positioned on the housing 1 adjacent the top of the casing 6. Extending through this opening is a vibratory conveyor 13 intended for supplying the tobacco leaves. The threshing wheel 5 is driven by a belt drive transmission 14, which in turn is driven by a motor (not shown).

Air is sucked into the separating chamber 7 through the fan (not shown) and suction pipe 2 via the annular opening between the housing 1 and the casing 9, through holes in the casing 9. In the upper part 3 of the chamber 3 some of the separating air will be sucked into the cap 10 at its lower portion and, after assing the cap 10, join the air, which has passed between e cap 10 and the housing 1. The top of casing 6 and the bottom of cap 10 forms an annular opening 3' Separation of the threshed tobacco is effected in the manner described in the above mentioned patent. However, because the lower end of the cap 10 extends down somewhat into the threshing chamber 3, some of the air, which is sucked up between housing 1 and the casing 6, will describe an S- curve downwards between the casing 6 and the cap 10, towards the upper side of the threshing wheel 5 and then up wards through the cap 10. A number of pure portions of leaves will be entrained by this air flow, whereas portions of leaves with stems attached, will be thrown down to the threshing wheel. It is important in the machine according to the invention that, because of the pressure difference prevailing between the lower and upper ends. of the cap 10, air is deflected from the space between the housing 1 and the cap 10 down into the space between the threshing chamber wall 6 and the lower part of cap 10 and further upwardly through the interior of cap 10 to a level above the upper portion of separating chamber 7. By this deflection of a portion of the air speed, the air speed in the upper portion of the space between housing 1 and cap 10 forming the upper portion of the separating chamber 7 is reduced to a desired value. In order to control the volume of the air flow, which is sucked up through the cap 10, it is, necessary to reduce the area of the cap 10, which reduction is preferably effected by designing the cap with a decreasing area at the upper end of the cap.

I claim:

l. A machine for threshing tobacco leaves and separating the threshed tobacco, comprising a threshing chamber having a vertical, substantially cylindrical open-topped wall, the lower portion of the wall provided with outlet openings for the threshed tobacco; a threshing wheel adjacent the outlet openings, a vertical shaft in the threshing chamber supporting the threshing wheel; means for supplying tobacco leaves to the threshing chamber; a vertical cap extending above the threshing chamber wall and positioned to provide an annular opening between the threshing chamber wall and the bottom of the cap whereby the annular opening is located above the threshing wheel; a tubular housing enclosing the threshing chamber and the cap; a separating chamber formed between the tubular housing and the cap; a suction pipe communicating with the upper portion of the tubular housing; the cap being tubular in shape and being provided with an open top and bottom, the open top being located centrally in the housing at a level above the separating chamber and the open bottom end extending into the open-topped portion of the threshing chamber. 2. A machine according to claim 1 further including a deflector means positioned on the tubular housing adjacent the annular opening to divert a portion of the air flow into and through the cap. 

